Blood pressure lowering efficacy of coenzyme Q10 for primary hypertension

Background Blood pressure is a commonly measured risk factor for non-fatal and fatal cardiovascular adverse events such as heart attacks and strokes. Clinical trials have suggested that coenzyme Q10, a non-prescription nutritional supplement, can effectively lower blood pressure (BP). When this review was completed and published in October 2009, it concluded that "due to the possible unreliability of the 3 included studies, it is uncertain whether or not coenzyme Q10 reduces blood pressure in the long-term management of primary hypertension." Objectives To determine the blood pressure lowering effect of coenzyme Q10 in primary hypertension. Search methods We searched the Hypertension Group Specialised Register (1946 to November 2015), The Cochrane Central Register of Controlled Trials (The Cochrane Library 2015, Issue 10), MEDLINE (1946 to November 2015), MEDLINE In-Process (accessed 10 November 2015), EMBASE (1974 to November 2015), Web of Science (1899 to November 2015), CINAHL (1970 to November 2015), and ClinicalTrials.gov (accessed 10 November 2015). We also searched reference lists of articles for relevant clinical trials in any language. Selection criteria Double blind, randomized, placebo-controlled parallel or cross-over trials evaluating the blood pressure (BP) lowering efficacy of coenzyme Q10 for a duration of at least three weeks, in patients with primary hypertension. Data collection and analysis The primary author determined trial inclusion, extracted the data and assessed the risk of bias. The second author independently verified trial inclusion and data extraction. Main results In this update of the review, one new randomized, controlled cross-over trial with a total of 30 participants was added, and one trial included in the initial review was excluded. Only two of the three included trials were pooled in the meta-analysis, as one trial was judged to have an unacceptably high risk of bias. In the meta-analysis of two RCTs (50 participants), coenzyme Q10 did not significantly change systolic BP: -3.68 mm Hg (95% confidence interval (CI) -8.86 to 1.49), or diastolic BP: -2.03 mm Hg (95% CI -4.86 to 0.81]), based on clinic data. Authors' conclusions This review provides moderate-quality evidence that coenzyme Q10 does not have a clinically significant effect on blood pressure. In one of three trials reporting adverse effects, coenzyme Q10 was well tolerated. Due to the small number of individuals and studies available for analysis, more well-conducted trials are needed.